1. Field of the Invention
The present invention relates to a heat-resisting supporting member, such as a skid button, provided on an upper surface of a skid in a heating furnace for directly supporting a heated material such as a steel material.
2. Description of the Prior Art
A steel material is transferred through an inside of a heating furnace to be heated at an appointed temperature. A skid supports the steel material during the transportation of the steel material. The skid has such a construction that a skid pipe for passing a cooling water therethrough is provided with a skid button fixedly mounted thereon for directly supporting the steel material and it is coated with an insulating material arranged along its periphery. And, this skid button must support the weight of the steel material in an atmosphere of high temperature, so that it is necessary for the skid button to have a great compression-creep strength at high temperature.
Accordingly, the skid button has been formed of heat-resisting steels or Co-base or Ni-Cr-base heat-resisting alloys or ceramics or composites comprising ceramics and metals.
It is necessary for the skid button formed of heat-resisting steels or alloys to be frequently renewed since a creep-deformation is generated on an upper surface of the skid button after using it for a long time in an atmosphere of high temperature, whereby a useful life time of the skid button is shortened. And, in order to reduce such a creep-deformation, a cooling water has been passed through said skid pipe but a problem has occurred in that a temperature of a portion brought into contact with the steel material is lowered, thereby generating skid marks on the steel material.
In order to solve the above described problem, a skid button formed of ceramics has been proposed. However, the conventional skid button of this type has a construction such that all of a surface brought into contact with a heated steel material is exposed to ceramics, so that a disadvantage has occurred in that a reaction occurs between the ceramics and oxidized scales or the atmosphere within the furnace causing wear of the ceramics. In addition, when the wear causes a difference of elevation on the skid button, or when the steel material is warped, a problem has occurred in that a shock load acts upon the skid button during the transportation of the steel material, whereby the ceramics are broken and scattered. Besides, the skid button formed of ceramics can not use welding as a means of fixedly mounting it on the skid pipe, so that it has required a special construction for fixedly mounting it on the skid pipe and has been expensive.